Optical fiber vibration sensing system for pipeline leakage detection

A technology for leak detection and fiber vibration, which is used in pipeline systems, mechanical equipment, gas/liquid distribution and storage, etc., and can solve problems such as increasing the complexity of the system structure, unstable control circuits and fiber winding structures, and unstable phase control.

Inactive Publication Date: 2012-01-11
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The PZT phase modulator is relatively easy to adjust, but the piezoelectric coefficient of the piezoelectric ceramic has a slight change during the voltage change, that is, the elongation has a certain nonlinearity with the voltage change, and the control circuit and the fiber winding structure may exist. Unstable, therefore, there is a certain instability in the phase control of this method
In addition, since the PZT phase modulator needs voltage control, it is an active device, which undoubtedly increases the complexity of the system structure and is not conducive to reducing costs

Method used

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  • Optical fiber vibration sensing system for pipeline leakage detection
  • Optical fiber vibration sensing system for pipeline leakage detection
  • Optical fiber vibration sensing system for pipeline leakage detection

Examples

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Embodiment Construction

[0038] like figure 1 As shown, we conducted an experiment with a water pipe instead of an oil pipeline. The length of the first delay fiber 3 used in the experiment is 3 km, the length of the sensing fiber 6 is 10 km, and the distance L from the leaking point of the water pipe 10 is 2× from the rightmost end of the sensing fiber 6. 2 The horizontal distance of the optical fiber coupler 8 is 7km, that is, the distance between the vibration point P and the third 2×2 optical fiber coupler at the rightmost end of the sensing fiber 6 is 7km, figure 2 Shown is the time-domain plot of the resulting sensing (interference) signal, image 3 shown as figure 2 The frequency domain diagram of the sensor signal shown after undergoing Fourier transform, wavelet transform and denoising, it can be clearly seen that the first "zero frequency" is located at f null = near 7.158kHz, according to formula (7), take c=3.0×10 8 m / s, n eff =1.5, the calculation can get x=6985m. The absolute erro...

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Abstract

The invention relates to an optical fiber vibration sensing system for pipeline leakage detection, which belongs to the technical field of optical fiber sensing and comprises a light source, a 3*3 optical fiber coupler, a first delay optical fiber, a first 2*2 optical fiber coupler, a second 2*2 optical fiber coupler, a sensing optical fiber, a second delay optical fiber, a third 2*2 optical fiber coupler and an optical detector. The optical fiber vibration sensing system is based on the Sagnac interference principle, the detection sensitivity and the stability of the sensing system are improved through adopting the introduction of fixed phase bias into the 3*3 optical fiber coupler, and the power of light returning the detector is enhanced through adding the optical fiber environment formed by the 2*2 optical fiber couplers, so the signal-to-noise ratio of the detector is improved, and the sensing distance is increased. The optical fiber vibration sensing system has the characteristics that the structure is simple, the sensitivity is high, and the stability is good. The optical fiber vibration sensing system can realize the real-time leakage detection on the transmission pipeline.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing and relates to pipeline leakage detection technology, in particular to a distributed optical fiber vibration sensing system for detecting whether pipelines are leaking. Background technique [0002] Traditional pipeline leak detection technology is difficult to achieve real-time and accurate monitoring in practical applications. With the development of optical fiber sensing technology, distributed optical fiber sensing technology is also gradually applied in the field of pipeline leakage monitoring. It has the characteristics of real-time, high sensitivity and easy laying that traditional pipeline leakage monitoring technology does not have. Distributed optical fiber vibration sensing technology is a new technology developed in recent years, which makes full use of the characteristics of the combination of "transmission" and "sensing" of optical fiber itself. [0003] Distributed op...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F17D5/02
Inventor 刘永梁文杰王智勇潘坤宋雷岳慧敏欧中华张利勋刘永智
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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